Golden Alexanders and the Black Swallowtail

Golden Alexanders

The cheerfully bright-yellow golden alexanders is an easy-to-grow native host in our area for the black swallowtail caterpillar—though the caterpillar will also eat the non-native Queen Anne’s Lace, parsley, and other plants of the Apiaceae, or carrot (sometimes called parsley), family. The plant has a wide range and can be found in the wild throughout the eastern United States, into Canada, and west to the Rocky Mountains.

Blooming midspring through June, golden alexanders grows in a range of soils, including clay and sand. It can take partial shade to full sun. While it likes wet soil, it will tolerate drying out, which makes it a good rain-garden plant.

Golden alexanders can get a little exuberant when it comes to reseeding, so, in small gardens where plant diversity is desired, plant it where there’s some shade, which dampens its enthusiasm a bit. For a more traditional look, cut off the spent flowers as their blooms fade. This keeps the plants tidy and also keeps reseeding to a minimum, preventing the creation of a little colony; though some gardeners revel in its tendency to fill space by spreading through seed. The pretty, spikey foliage and happy 3-inch yellow umbels make these plants worth the trouble—and what could be better than playing host to black swallowtail babies, some of whom will serve as food for breeding birds?